Modular microwave power divider-amplifier-combiner

Abstract

A power divider/combiner assembly is provided which matches the impedance seen at the input/output port with the impedance seen at the peripheral end of each of plural radial transmission lines. Impedance matching is accomplished through the use of an inverted microstrip on a substrate suspended over an air dielectric. The thickness of the air dielectric is varied along each transmission line in discrete steps from the common dividing/combining end to the peripheral end of each transmission line. The air dielectric thickness can be chosen independently for each section of line so that a characteristic impedance of from 40 ohms to greater than 130 ohms is achieved.

What is claimed is: 
     
       1. A power divider/combiner comprising: (a) a power input/output port having first and second ends and including one or more coaxial transmission line impedance transforming sections;   (b) a microwave energy radial divider/combiner section comprising a plurality of microwave energy transmission lines connected to and symmetrically radiating from the second end of the power input/output port to the outer edge of the divider/combiner section, each microwave transmission line comprising a microstrip conductor extending from the second end of the the power input/output port to the outer edge of the divider/combiner section; and   (c) means for transmitting microwave energy between the first end of the power input/output port and the ends of the transmission lines at the outer edge of the divider/combiner section, characterized in that the radial divider/combiner section includes an electrically conductive base surface, facing and fixably separated from the microstrip conductors, thereby forming a space between the microstrip conductors and the base surface, the space being filled with a dielectric medium, the distance of separation between the microstrip conductors and the base surface varying along the length of the transmission lines, such that an increasing impedance is attained from the outer edge to the second end of the power input/output port, and that the value of this increasing impedance, in conjunction with the value of the coaxial impedance transforming sections, is used to optimally match the impedance at the first end of the power input/output port with that at the ends of the transmission lines at the outer edge of the divider/combiner section.   
     
     
       2. The divider/combiner of claim 1 wherein the plural microwave energy transmission lines consist of twelve transmission lines. 
     
     
       3. The divider/combiner of claim 1 wherein the base surface comprises copper. 
     
     
       4. The divider/combiner of claim 1 wherein the dielectric medium is air. 
     
     
       5. The divider/combiner of claim 1 wherein the distance of separation between the microstrip conductors and the base surface varies in steps along the length of the transmission lines, the steps implementing impedance transforming section corresponding to that portion of an optimal transmission line impedance matching sequence of impedance values such that can be practically and efficiently realized through the use of microstrip transmission lines, each of the remaining values of the sequence being implemented by a corresponding coaxial impedance transforming section having an actual impedance value that is the quotient of its corresponding sequence impedance value divided by the number of microstrip transmission lines. 
     
     
       6. A divider/combiner comprising: (a) a radial divider/combiner section which comprises: (1) a base element of electrically conductive material, generally shaped like a disk, having a top surface and a bottom surface, the top surface facing the radial divider/combiner section and defined by a plurality of concentric circular annular planes, where each annular plane is parallel with every other annular plane,   (2) a planar substrate fixably separated from the base element and lying parallel to the plurality of annular planes, and   (3) a plurality of symmetrical radial microstrip lines deposited on the surface of the substrate that faces the radial divider/combiner section and the base element, and radiating from a common point at the center of the substrate surface to the outer edge of the substrate; and     (b) a coaxial transmission line power input/output port including one or more coaxial transmission line impedance transforming sections, disposed at the center of the base element, each of the plurality of concentric circular annular planes being disposed at preselected distances from the plurality of radial microstrip lines so as to discretely vary the impedance thereof, the preselected distances being chosen so as to effectively implement impedance transforming sections corresponding to that portion of an optimal transmission line impedance matching sequence of impedance values such that can be practically and efficiently realized through the use of microstrip transmission lines, each of the remaining impedance values of the sequence being implemented by a corresponding coaxial impedance transforming section having an actual impedance that is the quotient value of its correspondence sequence impedance value divided by the number of radial microstrip transmission lines.   
     
     
       7. The divider/combiner of claim 6 wherein the base element surface is defined by three concentric circular annular planes. 
     
     
       8. The divider/combiner of claim 6 wherein the depth of each annular plane below the top surface ranges from about 0.006 to 0.1 inch. 
     
     
       9. The divider/combiner of claim 6 wherein the substrate comprises quartz. 
     
     
       10. The divider/combiner of claim 6 wherein the substrate has the shape of a circular disk and the microstrip lines extend onto the surface of the outer edge of the substrate. 
     
     
       11. The divider/combiner of claim 6 wherein (a) the base has a circular hole therethrough located so that the center of the hole coincides with the center of the top surface of the base element, with a cylindrical tube, whose inner diameter is the same as the diameter of the hole in the base element, joined at one open end of the bottom surface of the base element so that the axis of the tube is aligned with the center of the hole in the base element; and   (b) an electrically conductive rod having a diameter smaller than that of the hole in the base element joined at one end to the common point at the center of the substrate surface and extending through the hole in the base element and through the center of the cylindrical tube to comprise a coaxial transmission line, with the axis of the rod coinciding with the axis of the tube, the center of the hole in the base element and the common point at the center of the substrate surface.   
     
     
       12. The divider/combiner of claim 11 wherein the electrically conductive rod comprises copper. 
     
     
       13. A modular power divider-amplifier-combiner comprising: (a) a radial microwave energy divider comprising: (1) a power input port having first and second ends and including one or more coaxial transmission line impedance transforming sections,   (2) a radial microwave energy divider comprising a plurality of microwave energy transmission lines connected to and symmetrically radiating from the second end of the power input port to the outer edge of the divider, each transmission line comprising a microstrip conductor extending from the second end of the power input port to the outer edge of the divider,   (3) means for transmitting microwave energy from the first end of the power input port through the coaxial impedance transforming sections to the divider;     (b) a plurality of amplifier modules, one for each transmission line, each amplifier associated with a different transmission line;   (c) means for conducting power from each transmission line to its associated amplifier module;   (d) a radial microwave energy combiner comprising: (1) a power output port having second ends and including one or more coaxial transmission line impedance transforming sections,   (2) a radial microwave energy combiner comprising a plurality of microwave energy transmission lines connected to and symmetrically radiating from the second end of the power output port to the outer edge of the combiner section, each transmission line comprising a microstrip conductor extending from the second end of the power output port to the outer edge of the combiner,   (3) means for transmitting microwave energy from the combiner to the first end of the power output port through the coaxial impedance transforming sections; and     (e) means for conducting power from each amplifier module to its associated transmission line, characterized in that the divider and combiner each include an electrically conductive base surface, facing and fixably separated from the microstrip conductors, thereby forming a space between the microstrip conductors and the base surface, the space being filled with a dielectric medium, the distance of separation between the microstrip conductors and the base surface varying along the length of the transmission lines such that an increasing impedance is attained from the outer edge to the second ends of the power input and output ports, respectively, and that the value of these increasing impedances, in conjunction with the values of the respective coaxial impedance transforming sections, are used to optimally match the respective impedances at the first ends of the power input and output ports with that at the ends of their associated transmission lines at the outer edge of the divider and combiner sections, respectively.   
     
     
       14. The divider-amplifier-combiner of claim 13 wherein the plural microwave energy transmission lines of the divider and combiner each consist of twelve transmission lines and wherein the plural amplifier modules consist of twelve modules. 
     
     
       15. The divider-amplifier-combiner of claim 13 wherein the divider and combiner base surfaces each comprise copper. 
     
     
       16. The divider-amplifier-combiner of claim 13 wherein the dielectric medium of the divider and combiner is air. 
     
     
       17. The divider-amplifier-combiner of claim 13 wherein the plural amplifier modules each comprise two hybrid-combined field effect transistors. 
     
     
       18. The divider-amplifier-combiner of claim 13 wherein the distance of separation between the microstrip conductors and the base surface varies in steps along the length of the transmission lines, the steps implementing impedance transforming sections corresponding to that portion of an optimal transmission line impedance matching sequence of impedance values such that can be practically and efficiently realized through the use of microstrip transmission lines, each of the remaining sequence values being implemented by a respective corresponding coaxial impedance transforming section having an actual impedance value that is the quotient of its corresponding impedance sequence value divided by the number of microstrip transmission lines. 
     
     
       19. A divider-amplifier-combiner comprising: (a) a microwave energy radial divider/combiner section which comprises: (1) a base element of electrically conductive material, shaped generally like a disk, having a top surface and a bottom surface, the top surface facing the radial divider/combiner section and defined by a plurality of concentric circular annular planes, where each annular plane is parallel with every other annular plane,   (2) a planar substrate fixably separated from the base element and lying parallel to the plurality of annular planes, and   (3) a plurality of symmetrical radial microstrip lines deposited on the surface of the substrate that faces the radial divider/combiner section and the base element, and radiating from a common point at the center of the substrate surface to the outer edge of the substrate; and     (b) a coaxial transmission line power input/output port including one or more coaxial transmission line impedance transforming sections, disposed at the center of the base element surface, each of the plurality of concentric circular annular planes being disposed at preselected distances from the plurality of radial microstrip lines so as to discretely vary the impedance thereof, the preselected distances being chosen so as to effectively implement impedance transforming sections corresponding to that portion of an optimal transmission line impedance matching sequence of impedance values such that can be practically and efficiently realized through the use of microstrip transmission lines, each of the remaining impedance values of the sequence being implemented by a corresponding coaxial impedance transforming section having an actual impedance value that is the quotient of its correspondence sequence impedance value divided by the number of radial microstrip transmission lines.   
     
     
       20. The divider-amplifier-combiner of claim 19 wherein the base element surface is defined by three concentric circular annular planes. 
     
     
       21. The divider-amplifier-combiner of claim 19 wherein the depth of each annular plane below the top surface ranges from about 0.006 to 0.1 inch. 
     
     
       22. The divider-amplifier-combiner of claim 19 wherein the substrate comprises quartz. 
     
     
       23. The divider-amplifier-combiner of claim 19 wherein the substrate has the shape of a circular disk and the microstrip lines extend onto the surface of the outer edge of the substrate. 
     
     
       24. The divider-amplifier-combiner of claim 19 wherein: (a) the base has a circular hole therethrough located so that the center of the hole coincides with the center of the top surface of the base element, with a cylindrical tube, whose inner diameter is the same as the diameter of the hole in the base element, joined at one open end of the bottom surface of the base element so that the axis of the tube is aligned with the center of the hole in the base element;   (b) an electrically conductive rod having a diameter smaller than that of the hole in the base element joined at one end of the rod joined to the common point at the center of the substrate surface and extending through the hole in the base element and through the center of the cylindrical tube to comprise a coaxial transmission line, with the axis of the rod coinciding with the axis of the tube, the center of the hole in the base element and the common point at the center of the substrate surface.   
     
     
       25. The divider-amplifier-combiner of claim 24 wherein the electrically conductive rods comprise copper.